Push button mechanism



Nov. 10, 1959 E. J. MAsTNEY ETAL 2,911,834

Fusi-:BUTTON MECHANISM 2 Sheets-Sheet 1 Filed Feb. 27. 1958 INVENTORS N64/.EW

5E. .1. MAsTNEY ETAL 2,911,834

PUSH BUTTON MECHANISM Nov. 10, 1959 2 Sheets-Sheet 2 Filed Feb. 27, 1958 United States Patent O PUSH BUTTON MECHANISM Edward J. Mastney, Berwyn, and John H. Williams, B arrington, Ill., assignors to Oak Mfg. Co., a corporation of Illinois Application February 27, 1958, Serial No. 717,948

15 Claims. (Cl. 7410.33)

This invention relates to a push buttonmechanism and more particularly to a mechanism having one or more push buttons for operating such devices as electric switches or the like. Push button mechanisms for use in connection with various types of apparatus are well known. As a rule, such push button mechanism may be provided with interlock means whereby a push button may be moved from a normal out position to a locked in position, interlock means being provided for releasing previously locked push buttons.

In prior interlocked push button mechanism, once a push button has been moved from an out to an in position, it has been necessary to use the interlock means for releasing the in button. Such a release usually operates on all in buttons.

This invention provides a mechanism wherein a plurality of push buttons are provided having stable in and out positions, said push buttons being independent of each other and a common means for unlocking all in buttons when such action is desired. This invention is an improvement upon the construction disclosed and claimed in United States application of John H. Williams, Serial No. 635,280, filed January 22, 1957, now Patent No. 2,857,781, issued October 28, 1958.

f The mechanism forming the subject matter embodying the present invention provides more positive operation. In order that the invention may be understood it will be described in connection with the drawings wherein exemplary embodiments are disclosed.

In the drawings:

Fig. l is a side view of a push button unit in out position. t

Fig. 2 is a view similar to Fig; l but showing a unit in a full in position preliminary to locking.

, Fig. 3 illustrates a push button unit after it has been locked to an in position.

Fig. 4 is a view showing a unit starting towards a full in position preliminary to being unlocked.

Fig. 5 is a view showing the unit in a full in unlocked position.

Fig. 6 is a detail illustrating the latch and latch bar.

Fig. 7 shows a modification.

One or more push button units may be mounted in a frame having front plate 10 and rear plate 11 maintained in spaced parallel relation by side plates not shown. A bottom plate 14 for carrying switches or other means operated by the push rods may be provided. Front plate 10 and rear plate 11 are provided with aligned slots for accommodating a number of push button units, one of which is here disclosed.

A push button unit, which may be indicated generally by 20, includes push rod proper 21 of ilat bar stock having reduced front portion 22 and reduced rear portion 23. Push rod 21 has finger 21a for operating a switch or other load. Front portion 22 passes through a suitable slot in front plate 12 and may have washer 425 of suitable flexible. material, as `rubber, disposed ICC around portion 22 for silencing the action of the push rod. Push rod 21 has shoulders 26 which may engage washer 25 to limit the outward movement of the push rod.

Reduced rear portion 23 of a push rod passes through a suitable slot in rear plate 11, this reduced portion extending from shoulders 27 of push rod 21. Between shoulders 27 and the opposed inside surface of rear plate 11 there is disposed coil spring 30 around reduced portion 23. Coil spring 30 will bias the push rod outwardly.

Push rod 21 is movable between end positions, ythe front position being determined by shoulders l26 on the push rod. The push rod cam'es a latch construction having a suitable lost motion mounting so that the latch may rock around some pivot axis and also may have some bodily movement along the line of rod movement and also transversely to the line of rod movement. In the specific construction disclosed herein, push rod 21 carries pivot pin 31 extending laterally therefrom.

Pin 31 is positioned on a forward portion of the push rod (the push button end is assumed to be the front). Floating on ypin 31 is latch 33 provided with aperture 34 into which pin 31 extends. Aperture 34 is L-shaped and has lateral branch a and longitudinal branch b. The aperture branches are just wide enough to accommodate pin 31. Thus branch a of the aperture permits bodily movement of the latch transversely of the push rod over a distance between two end positions determined by the length of branch a. Branch b permits longitudinal movement of the latch with respect to the push rod.

It is thus clear that the pin and aperture provide a lost motion mounting for the latch upon the push rod permitting the latch to rock at all times about some pivot axis and also permitting the latch to move bodily transversely of the rod movement from one position to another position and to move longitudinally with respect to the rod.

It is, of course, possible to reverse the pin and aper-I ture so that the pin is carried by the latch and the aperture, or a recess, with its two branches lies in the push rod. Other lost motion mountings' are possible.

As illustrated here, however, pin 31 carries latch 33 andV in order to lock the latch to its corresponding push rod, retaining washer 35 shown in outline is provided. Washer 35 maybe locked in position by a cotter pin or by staking the pin or in any other suitable fashion.

Latch 33 has cam portion 36 laterally offset from pin 31 or from the general region containing the axis around which the latch can rock. Cam portion 36 has a Ageneral toe shape.

Cooperating with cam portion 36 of the latch is cam` with outwardly bulging cam `surface 43 on latchA 33.-

Cam surface 43 and cam portion 36 of the latch are generally on opposite sides of pin 31. Thus asV illustrated,I

cam surface 43 of the latch is disposed rearwardly of pin 31. 'Ihis provides a force tending torock latch 33' in one direction and also tending to move the latch outwardly with'respect to the push rod and also tending to move latchr33 bodily to the right, as seen in Figures l and 2, against the cam plate. In fact, the rocking force isthe resultant of the two forces' tending `to move-the YPatented Nov. 10, 1959' 3 latch toward the blind ends of the L-shaped path of travel provided by the lost motion support of the latch on the push rod.

Latch 33 has detent head 46 which is adapted to cooperate with latch bar 47 extending transversely through window 57 of the push rod. Latch bar 47 may be fixed or movable. Latch bar 47 has inner edge 50 which may be engaged by detent head 46. Leaf spring 41 biases the latch so that the detent head is biased toward a latch engaging position. When the push rod is out, as seen in Fig. l for example, the detent head of the latch is stopped by the side of the latch bar. When the push rod is in far enough, the detent head can move to a locking position around the latching edge of the latch bar and engage edge Si) of the latch bar.

Latch 33 has body portion 33a which is provided with outwardly extending cam surface 33b for cooperation with outer edge 47a of latch bar 47.

A brief description of the locking and unlocking operation of a unit will now be given. Referring for example to Fig. l, the push rod is an extreme out position. In this position, pin 31 normally is at the blind end (rear) of the b branch of aperture 34. Leaf spring 41 biases the detent head of the latch toward the adjacent side face of the latch bar. Cam portion 38a in contacting toe 36 rocks latch 33 and causes detent head 46 to clear the latch bar sufficiently to prevent binding. Latch bar 47 may be moved longitudinally easily.

When the push rod is moved against its bias to an extreme in position as illustrated in Fig. 2, pin 31 of the push rod will urge latch 33 rearwardly, pin 31 still being at the blind or rear end of branch b of aperture 34. When the push rod has reached an extreme in position, as seen in Fig. 2, cam portion 36 of the latch will have cleared cam plate portions 37 and 38. At the same time, the latch detent head can engage the latch bar.

Upon release of the pressure upon the push rod, spring 30 urges the push rod outwardly a short distance. This causes pin 31 to move forwardly of branch b of aperture 34. The latch and cam plate are so proportioned that leaf spring 41 can move the latch so that pin 31 is in branch a of the latch aperture. Branch a is long enough so that latch toe 36 can take up the space separating it from the cam plate portion 39. Springs 30 and 41 cooperate to keep the parts in a stable locked in position, as illustrated in Fig. 3.

If the push rod as seen in Fig. 3 is pressed again, the unit will assume successively the positions illustrated in Figs. 4 and 5. Fig. 4 illustrates the initial movement during the unlocking stroke. Pin 31 moves the latch rearwardly. Leaf spring 41 rides forwardly of latch cam surface 43 and maintains its pressure on the latch. Bottom or outer edge 47a of the latch bar is engaged by cam surface 33b of latch 33. At the same time, latch toe 36 rides down on cam plate portion 39. Hence latch 33 will assume the position as seen in Fig. 5. The detent head will be somewhat beyond the latch bar edge 50. As Fig. shows, the latch body has moved to the right of pin 31 so that pin 31 is displaced along branch a of aperture 34, pin 31 being at the blind end of branch a. Spring 30 is strong enough to push rod 22 outwardly. As the push rod moves outwardly (down) from the position shown in Fig. 5, toe 36 of the latch engages cam part 39 and holds the latch in the position shown. This permits the detent head to clear the side of the latch bar. Spring end 42 bearing on part 43 keeps latch toe 36 against cam plate 39. As latch toe 36 moves to cam plate portion 38, the latch is forced bodily leftward, pin 31 being displaced along branch a toward branch b. When pin 31 is at the intersection of branches a and b the force of portion 42 of the leaf spring acting on cam surface 43 of the latch creates a longitudinal force on latch 33 to move the latch forwardly. Pin 31 is therefore displaced to the rear blind end of branch b as seen in Fig. 1. Cam portion 38a cooperates with spring portion 42 to position the latch as previously set forth.

In the discussion of the relative movements of pin 31 and latch 33, it is understood that the pin moves with rod 22. Latch 33 moves in various directions and causes the pin to be displaced along the branches of aperture 34.

To permit a push rod unit to be unlocked by means of the latch bar, edge 50 of the latch bar has slot 54 at a region normally offset from detent head 46. Upon movement of latch bar 47 to the right, slot 54 will be brought into registration with detent head 47. The bar material is tapered at bottom 55 of slot 54 so that the edge slopes toward detent head 46. This tapering portion 55 of slot 54 will function as a cam surface to aid in rocking latch 33 away from the latch bar when the push rod responds to spring 30 and moves to an out position. This taper may be omitted but is preferred to insure proper action at all times.

Latch bar 47 extends the entire length of the frame and passes through suitable slots or operings in the side plates. Latch bar 47 is biased by a spring to a normal position, where slot 54 is offset from detent head 46 of latch 33. By moving latch bar 46 to the right as seen in Fig. 6, slots 54 will be aligned with the respective detent heads and release the various push rod units for return to an unlocked position.

Cam trip portion 38a cooperates with latch part 36 to relieve the pressure of the detent head upon the side of latch bar 47. If latch bar 47 is of the movable type, this permits moving the latch bar by manual or power means without excessive friction. Thus, it is possible for a mechanism to have a large number of individual push button units. In case a substantial number of these units happen to be in the position illustrated in Fig. l, then pressure of detent heads upon the side of a latch bar would add up to a substantial load. By virtue of cam trip portion 38a, the movement of the latch bar will always present substantially the same load irrespective of the number of push button units and their positions.

Instead of having cam edge 33b on the latch for rocking the latch preliminary to unlocking the latch, it is possible to provide a modified construction as illustrated in Fig. 7. Referring to Fig. 7 the same general construction previously described is illustrated except that detent head 46 is provided with sloping cam edge 46a. Cooperating with cam edge 46a is stationary cam edge 60 carried by bracket 61 rigidly attached to rear plate 11.

It will be noted that in the locked in position, edges 46a and 60 are generally parallel and spaced from each other a short distance. The slopes of the cam edges are such that when the push rod is moved upwardly as seen in Fig. 7 (to the innermost position), the two cam edges will engage and will cause the latch to be rocked counter-clockwise with respect to pin 31. The rocking will cause detent head 46 to clear latch bar 47. Upon release of the push button from its innermost position, the latch will move downwardly or outwardly and nally end in the position illustrated in Fig. l. The clearances between edges 46a and 60 are small in practice and are not as large as illustrated in Fig. 7.

The various push rods cooperate with slidable portion 65 of suitable elect-ric switches.

What is claimed is:

1. A push-button operated mechanism comprising a push rod, means for supporting said push rod to be longitudinally movable between extreme out and in positions, means for biasing said push rod to an out position, a latch, lost motion means for supporting said latch on said rod, said lost motion means permitting rocking of said latch about a pivot axis and also permitting bodily movement of said latch in a generally Lshaped path, one pant of said L being substantially parallel to the path of rod movement, the other part of said L being substantially transverse to the path of rod movement, spring means for biasing said latch toward the blind ends of both parts of said L, means operating on said latch when the rod is disposed in the outer portion of its travel range for overcoming the spring bias tending to move the latch toward the blind end of the transverse L path portion, said latch including a detent head disposed inwardly of the lost motion mount, a latch bar for cooperation with said detent head, said latch and latch bar providing a locking engagement at an in rod position when said latch is free of said last named means and is subject only to said spring means, said mechanism being locked to an in position upon one rod movement in and being unlocked upon a succeeding in rod movement, said latch having a surface at a portion thereof which is adjacent the outer edge of the latch bar, said latch surface and latch bar edge being shaped so that upon unlocking movement of the push rod, said latch is rocked to move the detent head away from the latch for more positive unlocking action.

2. The mechanism according to claim l wherein the spring means for biasing the latch and the means operating on said latch for overcoming the spring bias act on opposite parts of the latch.

3. The mechanism according to claim 2 wherein said means operating on said latch for overcoming the spring bias includes a rigid plate having a cam surface generally parallel to the line of rod movement, said plate having a cam trip portion for engaging the latch to lessen latch pressure on said latch bar in the out position.

4. The mechanism according to claim 3 wherein said spring means for biasing the latch comprises a leaf spring, said latch having a suitable surface for cooperation with said leaf spring so that said latch is biased longitudinally of the rod in an out direction.

5. A push-button operated mechanism comprising a push rod, means for supporting said push rod for longitudinal movement between extreme out and in positions, means for biasing said rod to an out position, a latch, lost motion means for supporting said latch on said rod, said lost motion means including a pin and L-shaped recess providing an L-shaped path for permitting latch rocking and latch bodily movement parallel or transverse to the path of rod movement, spring means for biasing said latch toward the blind ends of both parts of said L path, means operating on said latch only when the rod is disposed in the outer portion of its travel range for overcoming the spring bias tending to move the latch transversely toward the blind end of the L, said latch including a detent head disposed inwardly of the lost motion mount, a latch bar for cooperation with said detent head, said latch and latch bar providing a locking engagement at an in rod position when said latch is free of said last named means and is subject only to said spring means, said mechanism being locked to an in position upon one rod movement in and being unlocked upon a succeeding in rod movement, said latch having a body portion adjacent the outer edge of the latch bar and having a cam portion which engages the outer edge of said latch bar when the latch is moved inwardly for unlocking said last named engaging action rocking the latch so that the detent head is positively moved laterally clear of the inner edge of the latch bar.

6. The mechanism according to claim 5 wherein said spring means for biasing the latch and the means operating on said latch are disposed on opposite sides of the lost motion means.

7. The mechanism according to claim 6 wherein said means operating on said latch comprises a stationary cam plate having an active cam surface extending generally parallel to the line of rod movement, said parallel surface being long enough so that said latch cooperates therewith over a substantial portion of the rod travel range beginning from an extreme out position and terminating short of the extreme in end of the rod travel range, said cam plate having a cam trip portion for cooperating with the latch only when in an out position d to relieve pressure of the latch upon the side of the latch bar.

8. A push-button operated mechanism comprising a push rod, means for supporting said push rod for longitudinal movement between extreme out and in positions, means for biasing said push rod to an out position, a latch, lost motion means for supporting said latch on said rod, said lost motion means permitting rocking of said latch about a pivot axis and also permitting bodily movement of said latch in a generally L-shaped path, one part of said L being substantially parallel to the path of rod movement, the other part ot said L being substantially transverse to the path of rod movement, said latch having an elongated portion extending inwardly from the lost motion support, said latch having a detent head on said elongated portion, a latch lbar for cooperation with said detent head, said latch bar extending perpendicularly to the plane of movement of said latch, spring means engaging a portion of said latch in wardly of said lost motion mount for biasing said latch toward the two blind ends of the L, said spring means also creating a rocking force on said latch tending to move the same toward said latch bar, said latch also having a camming portion laterally olfset from the lost motion mount in a direction generally parallel to the line of latch travel transversely of the rod path and away from the blind end of the L, a stationary cam plate cooperating with said camming portion, said stationary cam plate having a cam surface extending substantially parallel to the line of rod travel, said cam plate cooperatl ing with the camming portion of the latch only during the outermost part of the travel range of said rod, said cam plate and latch cooperating to force the latch to move transversely along the L path away from the blind end to the intersection of the two L path portions, said latch moving longitudinally of the rod toward the blind end of the L path portion when assuming an out position, said latch and latch bar providing a locking engagement when said latch camming portion is free of the straight part of said cam plate and is subject only to said spring means, said mechanism being locked to an in position upon one rod movement in and being unlocked upon a succeeding in rod movement, said latch having a cam portion adjacent the outer latch bar edge and engaging the same when said push rod is moved in for unlocking for more positive rocking of the detent head free of the latch bar.

9. The mechanism according to claim 8 wherein said spring means for said latch comprises a leaf spring, said latch having a curved surface cooperating with said leaf spring for creating the rocking force on said latch.

10. A push-button operating mechanism comprising a push rod, means for supporting said push rod to be longitudinally movable between extreme out and in positions, means for biasing said push rod to an out position, an elongated latch extending lengthwise of said rod, said latch having forward and rear portions, lost motion means for mounting the forward portion of said latch on said rod, said lost motion means permitting the latch to rock and also permitting bodily movement of the forward portion of said latch along a generally L- shaped path, the L-shaped path having portions substantially parallel and substantially transverse to the path of rod movement, spring means for biasing said latch toward the blind ends of both portions of said L-shaped path, said latch having a camming portion at the side thereof, said camming portion being laterally oifset from the lost motion mount, a liXed cam plate having a substantially straight cam surface extending generally parallel to the line of rod movement, said cam plate cooperating with the latch camming portion for overcoming the latch bias along the transverse part of the L, said cam plate being long enough to be eifective for a portion of the inward travel of the rod from an extreme outer position, said camming portion of the latch being free of the cam plate at an extreme in position of the push rod, said latch having a detent head at the rear portion thereof, a latch bar for cooperation with said detent head, said detent head and latch bar being adapted to have a locking engagement when the push rod reaches an in position, said latch responding to the rocking force to reach engagement, said latch having a cam portion adjacent the outer edge of the latch bar for cooperation therewith when said latch is moved inwardly from a locked in position for unlocking, said mechanism being adapted to be rocked upon one inward movement of the push rod from an out position, said locking position being an in position and said push rod having an extreme in position somewhat beyond the locking in position and rearwardly thereof, said mechanism being adapted to be unlocked when said push rod is moved from a locking to its extreme in position and then released, said latch being rocked to an unlocking position by the engagement of said latch cam portion and outer edge of said latch bar as well as the engagement of said cam plate upon the latch camming portion, said cam plate upon 4further outward movement of the push rod forcing said latch to move against its bias away from the blind end of the transverse portion of the L toward the intersection of the two L path portions whereupon the spring bias on the latch causes the latch to move toward the blind end of the longitudinal portion of the L.

11. The mechanism according to claim 10 wherein said spring means for biasing said latch comprises a leaf spring, said latch having a cam surface rearwardly of the lost motion mount, said leaf spring and cam surface on the latch cooperating to provide the rocking bias and the bias toward the blind ends of the L-shaped path.

12. The construction according to claim l1 wherein said latch bar and leaf spring are on opposite sides of the latch and wherein the xed cam plate is also on the side of the .latch opposite to the spring engaging portion of the latch and wherein said cam plate has a cam trip portion for cooperating with the latch only in the out position to relieve the detent pressure on the latch bar.

13. A push-button operated mechanism comprising a push rod, means for supporting said push rod to be longi- CII tudinally movable between extreme out and in positions, means for biasing said push rod to an out position, a latch, lost motion means for supporting said latch on said rod, said lost motion means permitting rocking of said latch about a pivot axis and also permitting bodily movef ent of said latch in a generally L-shaped path, one part of said L being substantially parallel to the path of rod movement, the other part of said L being substantially transverse to the path of rod movement, spring means for biasing said latch toward the blind ends of both parts of said L, means operating on said latch when the rod is disposed in the outer portion of its travel range for overcoming the spring bias tending to move the latch toward the blind end of the transverse L path portion, said latch including a detent head disposed inwardly of the lost motion mount, a latch bar for cooperation with said detent head, said latch and latch bar providing a locking engagement at an in rod position when said latch is free of said last named means and is subject only to said spring means, said mechanism being locked to an in position upon one rod movement in and being unlocked upon a succeednig in rod movement, and means including a cam surface on said latch operative only when said rod is in an in position for positively rocking the latch so that the detent head clears the latch bar in preparation for moving to an out position.

14. The mechanism according to claim 13 wherein said last named means includes a member which is normally stationary with relation to the latch and has a surface which cooperates with the latch cam surface.

15. The mechanism according to claim 14 wherein said stationary member has a cam surface cooperating with a cam surface located at the latch detent head.

References Cited in the le of this patent UNlTED STATES PATENTS 766,865 Baxter Aug. 9, 1904 1,257,062 Adams Feb. 19, 1918 1,695,178 Clement Dec. 11, 1928 2,459,255 Von Glahn Jan. 18, 1949 2,471,568 Harrison May 31, 1949 2,848,900 Teaf Aug. 26, 1958 

